@leocg what is this standard you're talking about?
I see that every browser or desktop notification has content and even the chrome extension that uses the same engine (webogram) shows a preview.
The fact that you can choose in the settings to choose an overview of the message (same settings of the chrome extension) indicates that is a bug.

I will like more the Opera extension because it is integrated in the Opera panel (the chrome extension will load as a separate process, that make it less appealing than the desktop version) and I don't think I'm the only one, so I think that very few have this problem